The biggest, most sophisticated Mars rover ever built - a car-sized vehicle bristling with cameras, microphones, drills and lasers - blasted off for the red planet yesterday as part of an ambitious, long-range project to bring the first Martian rock samples back to Earth, to be analysed for evidence of ancient life.
Nasa's Perseverance rode a mighty Atlas V rocket into a clear morning sky in the world's third and final Mars launch of the summer. China and the United Arab Emirates got a head-start last week, but all three missions should reach their destination in February after a journey of seven months and 480 million kilometres.
The plutonium-powered, six-wheeled rover will drill down and collect tiny geological specimens that will be brought home in about 2031 in a sort of interplanetary relay race involving multiple spacecraft and countries. The overall cost is more than $8bn (€6.75bn).
Nasa's science mission chief, Thomas Zurbuchen, pronounced the launch the start of "humanity's first round trip to another planet".
In addition to potentially answering one of the most profound questions of science - Is there or has there ever been life beyond Earth? - the mission will yield lessons that could pave the way for the arrival of astronauts as early as the 2030s.
"There's a reason we call the robot Perseverance. Because going to Mars is hard," Nasa Administrator Jim Bridenstine said just before lift-off. "In this case, it's harder than ever before because we're doing it in the midst of a pandemic."
Shortly after lift-off, Perseverance unexpectedly went into safe mode, a sort of protective hibernation, after a temperature reading triggered an alarm. But deputy project manager Matt Wallace later said that the spacecraft appeared to be in good shape, with its temperatures back within proper limits, and that NASA will probably switch it back to its normal cruise state within a day or so.
"Everything is pointing toward a healthy spacecraft ready to go to Mars and do its mission," he said.
Nasa's deep-space tracking stations also had some difficulty locking on to signals from Perseverance early in the flight but eventually established a solid communication link, Mr Wallace said.
The US, the only country to safely put a spacecraft on Mars, is seeking its ninth successful landing on the planet, which has proved to be the Bermuda Triangle of space exploration, with more than half of the world's missions there burning up, crashing or otherwise ending in failure.
China is sending both a rover and orbiter. The UAE, a newcomer to outer space, has an orbiter en route.
The opportunity to fly between Earth and Mars comes around only once every 26 months when the planets are on the same side of the sun and about as close as they can get.